Evaluation of the bioformulation of potent native strains of Trichoderma spp. against the foot rot/gummosis of Kinnow mandarin

Abstract

Background: Foot rot/gummosis of citrus, caused by Phytophthora spp., is the most important disease of citrus, responsible for the yield losses of 10 to 30% in fruit production in major citrus growing countries. Considering the burden of disease, the present study was undertaken to evaluate different native potent strains of Trichoderma spp. against the foot rot/gummosis of citrus. Results: Based on molecular characteristics, i.e., ITS ribosomal DNA sequence analysis, 3 isolates of Phytophthora nicotianae var. parasitica and 7 isolates of Trichoderma (6 isolates of T. asperellum and one of T. harzianum) were identified. Trichoderma isolates and Metalaxyl-M + Mancozeb were used to assess antagonistic activity against the foot rot/gummosis under field conditions. T. asperellum T20 mutant reduced gummosis lesion size (95.67%), improved feeder root density (0.0236 cm3), increased number (990.16), and yield of fruits (168.83 kg). Conclusions: The talc-based bioformulation of T20 mutant (T. asperellum) strain, used as a soil treatment, was able to manage effectively the gummosis/foot rot of citrus and also exhibited the highest yield.